Field of the Invention
This invention relates to cryogen gas purifiers for removing contaminants from a supply of cryogen gas and providing a purified source of cryogen gas to equipment such as liquefiers and the like; and more particularly the invention relates to helium gas purifiers configured to utilize the cooling power of a cryocooler to coalesce impurities within the helium gas for filtration through a filtering medium.
Description of the Related Art
Cryogen gases are in high demand for their application in refrigeration and cooling technologies, as well as other applications. For example, helium gas, among other cryogen gases, is often used in a variety of medical and scientific equipment, including magnetic resonance imaging (MRI), material analysis devices, and other equipment. To achieve liquid-phase helium for use with refrigeration technologies, gas-phase helium is generally liquefied within a gas liquefier by cooling the gas to a point of liquefaction. The liquid-phase helium is then evaporated to produce a flow of gas-phase helium for cooling material samples, super magnets, or other materials or components.
It is often desirable to supply high-purity helium gas to a liquefier such that accumulation of contaminants within the liquefier can be minimized, thus reducing lost time and resources attributed to equipment maintenance procedures. Moreover, certain liquefiers and other instruments benefit from the use of a high-purity cryogen gas. For example, to effectuate a specialized operation, such as high performance liquefaction, where efficient liquefaction is obtained using a pressure-controlled liquefaction region and purified helium gas as described in commonly owned U.S. Publication No. 2013/0014517, titled “LIQUEFIER WITH PRESSURE-CONTROLLED LIQUEFACTION CHAMBER”; the contents of which are incorporated by reference.
As is indicated above, as cryogen gas is condensed into liquid during a liquefaction process within a suitable liquefier, various impurities such as nitrogen, oxygen, and other impurities tend to collect within the system, thus giving rise to required maintenance. Typical maintenance may include warming the liquefier to ambient temperatures to clean out any impurities, wherein the warming cycle may require several hours or days to complete. Thus, in many cases the liquefier may be inoperable or unavailable for extended maintenance periods.
There is a need for purified cryogen gas, such as helium gas, being substantially free of contaminants, such that liquefiers and other equipment can be utilized with minimal interference associated with maintenance requirements. This need is further enhanced by such cryogen gas purifiers, or “scrubbers”, being configured to quickly and efficiently provide a supply of purified cryogen gas. Additionally, such a purifier, or scrubber, configured for continuous operation without being limited by maintenance procedures is an added valuable improvement in the art.